The Kawasaki rider won the opening race at the final round of the 2018 championship at the Losail International Circuit in Qatar on Friday, beating team-mate Tom Sykes over the line by 1.4 seconds.
Rea, who has now chalked up 11 wins in a row, can surpass American rider Polen’s benchmark with victory in race two on Saturday.
He said: “It’s mad. Not that I was lucky to get it done, but I ran into problems near the end with my front tyre on the right side and it looks like a qualifying tyre.
“I just really struggled and I need to revisit that tomorrow, especially coming through (from row three) when I will be battling traffic. I had my eye on this 17-win record because everyone has been talking about it since I beat Carl Fogarty’s 59 wins.
“I can’t quite believe it and I’m very fortunate to be in this position with the team,” added Rea.
“They gave a me great bike today and I could do what I liked, although the front tyre was a little critical at the end.”
Another win in the final race would also see the Ulster rider smash his own benchmark of 556 championship points, which he set in 2017 en-route to his third world crown.
Rea is also on the verge of a record sixth consecutive double as he aims to finish the season unbeaten since Laguna Seca in the USA in June.